A structure of this type of filter known heretofore (e.g. from JP-A-03-71710) is shown in FIG. 13 and FIG. 14. In FIG. 13, numerals 70 to 76 denote green sheets of a dielectric material, wherein the green sheets 71 and 72 are provided with electrodes 77, 78, 79, 80 for capacitors. On the other hand, the green sheet 74 is provided with electrodes 81 and 82 for coils, while the green sheet 76 is provided with shielding electrodes 83 and 84. The green sheets 70-76 shown in FIG. 13 are laminated and subsequently fired at such a temperature at which the electrodes 77-84 (e.g. of silver or copper) do not make disappearance, whereby these sheets are integrated in such a structure as shown in FIG. 14. In FIG. 14, numerals 85 and 86 denote input/output terminals. Thus, in the filter known heretofore, capacitors are formed by the electrodes 77-80 disposed in opposition, while coils are formed by the electrodes 81 and 82, wherein the filter is constituted by these capacitors and coils.
A problem of the prior art filter described above is seen in that satisfactory filter characteristics can not be obtained because no-loaded Q of a resonator comprising the capacitor and the coil can not be made high. More specifically, referring to FIG. 13, since the green sheets 70 to 76 are allowed to be fired only at a temperature at which the electrodes 77-84 can not disappear, significant dielectric loss is incurred, as a result of which a constant indicating low loss of the resonator (no-loaded Q) assumes a small value. Consequently, the filter comprising the resonators each having low unloaded Q suffers significant insertion loss in the pass-band with the characteristic in the attenuation band being damped. Thus, it is impossible to use the filter in such applications in which the requirement for the characteristic requirement is severe.